The move comes as Japan aims to increase its annual ammonia fuel demand to three million tonnes by 2030 from zero now and to create a new supply chain of the fuel in a bid to cut CO2 emissions and combat climate change.

Ammonia is used for fertiliser and industrial materials worldwide, but the compound, which does not emit carbon dioxide when burned, is seen as an effective future energy source along with hydrogen.

Mitsubishi has signed a memorandum of understanding with the ammonia producer PAU, Japan Oil, Gas and Metals National Corporation (JOGMEC) and Indonesia's university Bandung Institute of Technology to conduct a joint study on CCS and carbon dioxide utilisation for production of ammonia fuel from natural gas, it said.

The four parties will conduct a CCS feasibility study near PAU's ammonia plant in Luwuk, Central Sulawesi, and Mitsubishi's Donggi-Senoro liquefied natural gas (LNG) plant in the same province, with an aim to store carbon dioxide generated during the production phase.

"Our goal is to convert PAU's ammonia plant to produce 700,000 tonnes of clean ammonia fuel a year in about five years and export the fuel to Japanese coal-fired power plants," a spokesman for Mitsubishi said.

PAU, in which Mitsubishi holds a stake, currently exports ammonia for use in fertilisers, plastics and chemicals to Asian countries, including Japan, South Korea and China, the spokesman said.

Last year, Japan's biggest power generator JERA said it wanted to use ammonia in its coal-fired plants to help cut carbon emissions starting in 2030.

(Reporting by Yuka Obayashi. Editing by Mark Potter)